Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The process of dissolving involves particles of the solute fitting into the spaces between the particles of the solvent. Even though the solid 'disappears' from sight, its particles are still present in the liquid.
Sieving is a physical method of separation. It works because the holes in the sieve allow particles smaller than the holes to pass through while trapping larger particles.
📐Formulae
💡Examples
Problem 1:
If you stir of salt into of water until it all dissolves, what will the total mass of the salt solution be?
Solution:
Explanation:
According to the principle of conservation of mass, the mass of the solution is the sum of the mass of the salt and the mass of the water.
Problem 2:
You have a mixture of dried peas and flour. Which tool would you use to separate them and why?
Solution:
A sieve.
Explanation:
The flour particles are very small and will pass through the holes of the sieve, while the dried peas are larger than the holes and will remain on top.
Problem 3:
Classify the following as Soluble or Insoluble in water: (a) Sand, (b) Sugar, (c) Cooking Oil, (d) Coffee granules.
Solution:
(a) Insoluble, (b) Soluble, (c) Insoluble, (d) Soluble
Explanation:
Sugar and coffee granules dissolve to form a solution. Sand does not dissolve and will settle at the bottom. Oil does not dissolve and usually floats on top of the water.